Which statement about ideal oil is true?

• A. It is cheap and widely available
• B. It is not necessarily suitable for all refrigerants
• C. It is best at handling high temperatures and high pressures
• D. It never mixes with refrigerants

Answer: (C)

The key idea is that the oil in a refrigeration system must keep delivering lubrication even under the harsh conditions inside the compressor. As the refrigerant is compressed, temperatures soar and pressures rise. The ideal oil needs to stay chemically stable and retain the right viscosity across those conditions so it can form a reliable lubricating film and prevent wear. That’s why the statement about handling high temperatures and high pressures is true: it captures the essential requirement for protecting the compressor and keeping the system running smoothly.

Prices or availability don’t guarantee performance, and an ideal oil is chosen for compatibility with the refrigerant rather than a blanket claim of incompatibility or universal immiscibility. Some oils are designed to mix with certain refrigerants to ensure proper lubrication, so saying it never mixes with refrigerants isn’t accurate.